People with (probably) fake accounts forcing XP on people is an issue that's been brought up on the Facebook page and here as well. Doing this ruins some people's strategy of remaining on lower levels while they build up their pop points. There's no real recourse because it's very likely from fake accounts.

My suggestion to combat this would be to make gathering XP after being attacked a manual thing, much like the Daily Tasks. This way, people who don't mind getting XP could get it, but those who don't can ignore it. This would take power away from those trying this attempt to ruin others' gameplay.

This would only affect when someone has been attacked. When someone attacks a higher level, the XP would work the same, since the player is making the choice to attack and get XP.